jim agrees to sell his rolex watch to joe for $3,500. jim and joe each sign a written contract outlining the terms of the sale. jim has second thoughts since it was a gift from his ex-wife tammy. jim calls joe and tells him that he does not wish to sell the watch. joe agrees to discharge the contract. three months later, joe finds out that jim's watch is actually worth $75,000. joe demands to buy the watch for the $3,500 contract price. is jim liable to sell the watch to joe?